How to defeat mega mewtwo y?

my friend have a unbeateble Mega Mewtwo y. I have already a tactic ( delphox trick room and mystical fire) only it isn’t good enough what are other ways to defeat a Mega mewtwo y with sp attack 480 ,speed 400 and the moves: ice beam thunderbolt psychic and psystrike?

Pleaselog inorregisterto add a comment.

Bisharp is your man.

Mew2slayer (Bisharp)@ Focus SashAdamant | Defiant4 HP / 252 Atk / 252 Spe- Sucker Punch- Knock Off- Iron Head- Low Kick

Your friend’s Mewtwo has all attacking moves. Therefore, a Sucker Punch is gurarunteed unless he switches and guaruntees a KO. Knock Off actually has a chance to KO too if you fear a switch.

If you’re afraid he’ll predict Sucker Punch and switch Mewtwo out, you could always trap it with a move like Block, Spider Web or Mean Look.Meowstic-Mgets both Prankster and Mean Look, ensuring that you trap Mewtwo.

But when Meowstic switches to Bisharp, the trapping effect wears off.

^ I forgot this. If you’re desparate, Bisharp gets Mean Look, and the Focus Sash ensures you get one in.

You could use a bug type Like Volcarona Or a Dark type since Physic attacks do nothing to them,Bisharp would be a good one or a Umbreon

So there are some good answers here. But I always had a tactic for mega mewtwo Y. Take a Yanmega, modest, Max IVs sp attack and speed. Then Teach it Bug Buzz. It should have the ability Speed Boost. Make it hold Life orb.Send it out on battle and use protect. You will get a speed boost this way. Next turn hit mewtwo with Bug Buzz witch is STAB and life orb boosted. Gg